4,837 research outputs found
Hadronic Calorimeter Shower Size: Challenges and Opportunities for Jet Substructure in the Superboosted Regime
Hadrons have finite interaction size with dense material, a basic feature
common to known forms of hadronic calorimeters (HCAL). We argue that
substructure variables cannot use HCAL information to access the microscopic
nature of jets much narrower than the hadronic shower size, which we call
superboosted massive jets. It implies that roughly 15% of their transverse
energy profile remains inaccessible due to the presence of long-lived neutral
hadrons. This part of the jet substructure is also subject to order-one
fluctuations. We demonstrate that the effects of the fluctuations are not
reduced when a global correction to jet variables is applied. The above leads
to fundamental limitations in the ability to extract intrinsic information from
jets in the superboosted regime. The neutral fraction of a jet is correlated
with its flavor. This leads to an interesting and possibly useful difference
between superboosted W/Z/h/t jets and their corresponding backgrounds. The QCD
jets that form the background to the signal superboosted jets might also be
qualitatively different in their substructure as their mass might lie at or
below the Sudakov mass peak. Finally, we introduce a set of zero-cone
longitudinal jet substructure variables and show that while they carry
information that might be useful in certain situations, they are not in general
sensitive to the jet substructure.Comment: 6 pages, 4 figures; v2: minor improvements of presentation; published
versio
VICAR-DIGITAL image processing system
Computer program corrects various photometic, geometric and frequency response distortions in pictures. The program converts pictures to a number of elements, with each elements optical density quantized to a numerical value. The translated picture is recorded on magnetic tape in digital form for subsequent processing and enhancement by computer
THE SENSITIVITY OF THE GREENHOUSE EFFECT TO CHANGES IN THE CONCENTRATION OF GASES IN PLANETARY ATMOSPHERES
We present a radiative transfer model for Earth-Like-Planets (ELP). The model allows the assessment of the effect of a change in the concentration of an atmospheric component, especially a greenhouse gas (GHG), on the surface temperature of a planet. The model is based on the separation between the contribution of the short wavelength molecular absorption and the long wavelength one. A unique feature of the model is the condition of energy conservation at every point in the atmosphere. The radiative transfer equation is solved in the two stream approximation without assuming the existence of an LTE in any wavelength range. The model allows us to solve the Simpson paradox, whereby the greenhouse effect (GHE) has no temperature limit. On the contrary, we show that the temperature saturates, and its value depends primarily on the distance of the planet from the central star. We also show how the relative humidity affects the surface temperature of a planet and explain why the effect is smaller than the one derived when the above assumptions are neglected
A variant of the Mukai pairing via deformation quantization
We give a new method to prove a formula computing a variant of Caldararu's
Mukai pairing \cite{Cal1}. Our method is based on some important results in the
area of deformation quantization. In particular, part of the work of Kashiwara
and Schapira in \cite{KS} as well as an algebraic index theorem of Bressler,
Nest and Tsygan in \cite{BNT},\cite{BNT1} and \cite{BNT2} are used. It is hoped
that our method is useful for generalization to settings involving certain
singular varieties.Comment: 8 pages. Comments and suggestions welcom
Immigration Detention: Perspectives from Maine Law Students Working on the Ground at the Laredo Detention Center in Texas
Since 2017, students enrolled in the University of Maine School of Law Refugee and Human Rights Clinic have traveled to Laredo, Texas to participate in a program, sponsored and run by the law firm Jones Day in collaboration with Texas RioGrande Legal Aid, to provide representation for women in the Laredo Detention Center. Alongside Jones Day attorneys, the students conduct client intake interviews, draft memos detailing each woman’s experiences and any potential legal claims, and assist in the representation of clients. This article will provide a glimpse into the experiences of three Maine Law student attorneys during their time in Laredo, Texas, and will survey issues in the contemporary immigration landscape: first, an overview of the political climate surrounding the immigration debate, current immigration trends, and statistical figures; second, stories providing context for why people are seeking to immigrate to the U.S., and the persecution and challenges faced by immigrant women; third, the shortage of representation for immigrants, whether detained or non-detained; and finally, one of the most challenging and poignant issues encountered by student attorneys participating in the Laredo Project—the separation of immigrant mothers from their children
A Method of Drusen Measurement Based on the Geometry of Fundus Reflectance
BACKGROUND: The hallmarks of age-related macular degeneration, the leading cause of blindness in the developed world, are the subretinal deposits known as drusen. Drusen identification and measurement play a key role in clinical studies of this disease. Current manual methods of drusen measurement are laborious and subjective. Our purpose was to expedite clinical research with an accurate, reliable digital method. METHODS: An interactive semi-automated procedure was developed to level the macular background reflectance for the purpose of morphometric analysis of drusen. 12 color fundus photographs of patients with age-related macular degeneration and drusen were analyzed. After digitizing the photographs, the underlying background pattern in the green channel was leveled by an algorithm based on the elliptically concentric geometry of the reflectance in the normal macula: the gray scale values of all structures within defined elliptical boundaries were raised sequentially until a uniform background was obtained. Segmentation of drusen and area measurements in the central and middle subfields (1000 μm and 3000 μm diameters) were performed by uniform thresholds. Two observers using this interactive semi-automated software measured each image digitally. The mean digital measurements were compared to independent stereo fundus gradings by two expert graders (stereo Grader 1 estimated the drusen percentage in each of the 24 regions as falling into one of four standard broad ranges; stereo Grader 2 estimated drusen percentages in 1% to 5% intervals). RESULTS: The mean digital area measurements had a median standard deviation of 1.9%. The mean digital area measurements agreed with stereo Grader 1 in 22/24 cases. The 95% limits of agreement between the mean digital area measurements and the more precise stereo gradings of Grader 2 were -6.4 % to +6.8 % in the central subfield and -6.0 % to +4.5 % in the middle subfield. The mean absolute differences between the digital and stereo gradings 2 were 2.8 +/- 3.4% in the central subfield and 2.2 +/- 2.7% in the middle subfield. CONCLUSIONS: Semi-automated, supervised drusen measurements may be done reproducibly and accurately with adaptations of commercial software. This technique for macular image analysis has potential for use in clinical research
Courant-Dorfman algebras and their cohomology
We introduce a new type of algebra, the Courant-Dorfman algebra. These are to
Courant algebroids what Lie-Rinehart algebras are to Lie algebroids, or Poisson
algebras to Poisson manifolds. We work with arbitrary rings and modules,
without any regularity, finiteness or non-degeneracy assumptions. To each
Courant-Dorfman algebra (\R,\E) we associate a differential graded algebra
\C(\E,\R) in a functorial way by means of explicit formulas. We describe two
canonical filtrations on \C(\E,\R), and derive an analogue of the Cartan
relations for derivations of \C(\E,\R); we classify central extensions of
\E in terms of H^2(\E,\R) and study the canonical cocycle
\Theta\in\C^3(\E,\R) whose class obstructs re-scalings of the
Courant-Dorfman structure. In the nondegenerate case, we also explicitly
describe the Poisson bracket on \C(\E,\R); for Courant-Dorfman algebras
associated to Courant algebroids over finite-dimensional smooth manifolds, we
prove that the Poisson dg algebra \C(\E,\R) is isomorphic to the one
constructed in \cite{Roy4-GrSymp} using graded manifolds.Comment: Corrected formulas for the brackets in Examples 2.27, 2.28 and 2.29.
The corrections do not affect the exposition in any wa
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